Speed and accuracy in movement timing

Abstract

This study examined how speed was related to movement accuracy in terms of impulse variability. Impulse variability model had a significant role in explaining movement accuracy, but the model turned out to have some limitations for generalization. Therefore, there was a need to identify how kinetic parameter (force, impulse duration) changes were related to the kinematic error variability (timing accuracy, spatial accuracy). A new prediction in speed and accuracy is that spatial accuracy is proportional to the impulse variability multiplied by each movement time. Force parameter scaling (Experiment 1), time parameter scaling (Experiment 2), and the scaling of both parameters (Experiment 3) were employed so that movement accuracy could be examined in a full range of force production. When three experiments were combined for analysis, impulse variability explained only about 29% of the variance of variable spatial error. However, variable spatial error was explained by impulse variability multiplied by movement time with an R$\sp2$ of.950. This is a good evidence that movement time is an important variable in explaining variable spatial error in addition to impulse variability. The results suggested that spatial accuracy or timing accuracy was not a function of speed in general and that the function between speed and accuracy changed depending on the scaling strategies of the force and time parameter. It was also shown that the rate of force production was an important variable in predicting timing accuracy.